NASA TV(HOUSTON) -- Space shuttle Endeavour and its crew will finally return to Earth early Wednesday morning, completing one of NASA's final shuttle flights, a program that was launched almost 30 years ago.

Having departed the International Space Station late Sunday, Endeavour's entry flight control team will evaluate weather conditions at the landing site at Merritt Island, Florida before giving the approval to land, according to NASA

The 25th and final flight for Endeavour also marks the final shuttle flight for the six-man crew aboard Endeavour. The seasoned astronauts are wrapping up a 16-day mission, during which they completed assembly of the U.S. section of the International Space Station.

"To see the horizon out there, with all that hardware beneath you and to understand what we've done as a nation and as a world to build that international space station; it's spectacular," Astronaut Drew Feustel said.

Spacewalker Fincke, who has spent months living on the space station in years past, now holds the U.S. record for time in space, at 380 days. "I hope my record is soon broken," Fincke said.

The most important project on this journey for the crew is to aid in the explanation of possible origins of the universe; the astronauts hauled Endeavour into space so they can search for "unusual" kinds of matter.

Endeavour delivered a $2 billion cosmic ray detector, called Alpha Magnetic Spectrometer-2 (AMS), which will remain on the space station for the next decade. The cosmic ray detector is searching for antimatter and dark matter, which scientists hope will shed light on the origins of the universe.

The mission, which also included adding finishing touches on the orbiting lab while adding an extension beam and a platform full of spare parts, has been a complete success for NASA. ﻿